I am an Oracle DBA.
I do not have a CS degree.
I can answer most of these programming questions. Well I can answer all the coding ones. May not always be the best code or in C ( I have not used C in 10 years)
That being said, I have no idea what the answer to the hexadecimal one is ,but I can google it in 5 minutes. When would I use hexadecimal given what I do?
About the one where you change what you print out based on base 3 or base 5. I know you use modulus for this. However, this is the kind of thing that would slip out of my head some times, since I rarely use modulus when I script or code. So it is easy for me to forget.

I find it difficult to believe, but the reports keep pouring in via Twitter and email: many candidates who show up for programming job interviews can't program. At all. Consider this recent email from Mike Lin: The article Why Can't Programmers... Program? changed the way I did interviews. I ...